1. Field of the Invention
The present invention generally relates to a client apparatus, an image display controlling method, a shared virtual space providing apparatus and a method thereof, and program providing medium. More particularly, the present invention relates to a client apparatus, an image display controlling method, a shared virtual space providing apparatus and a method thereof, and program providing medium that are capable of growing a virtual creature object in a process closer to that of a real creature.
2. Description of Related Art
A cyberspace service named Habitat (registered trademark) is known in so-called personal computer communications services such as NIFTY-Serve (registered trademark) of Japan and CompuServe (registered trademark) of US in which a plurality of users connect their personal computers via modems and public telephone networks to the host computers installed at the centers of the services to access them in predetermined protocols. Development of Habitat started in 1985 by Lucas Film of the US, operated by Quantum Link, one of US commercial networks, for about three years. Then, Habitat started its service in NIFTY-Serve as Fujitsu Habitat (trademark) in February 1990.
In Habitat, users can send their alter egos called avatars (the incarnation of a god figuring in the Hindu mythology) into a virtual city called Populopolis drawn by two-dimensional graphics to have a chat (namely, a realtime conversation based on text entered and displayed) with each other. For further details of Habitat, refer to the Japanese translation pp. "282-307" of "Cyberspace: First Steps," Michael Benedikt, ed., 1991, MIT Press Cambridge, Mass., ISBN0-262-02327-X, the translation being published Mar. 20, 1994, by NTT Publishing, ISBN4-87188-265-9C0010.
In the conventional cyberspace systems operated by personal computer communications services such as mentioned above, a virtual street and the inside of a room, for example, are drawn in two-dimensional graphics. Therefore, moving an avatar in the depth direction is realized simply by moving it up and down in the background of the two-dimensional graphics. This is a poor way of simulating walking and movement in a virtual space. Also, the two-dimensional virtual space in which a user's avatar and the avatar of another user are displayed is viewed from a viewpoint of a third party, thereby impairing the sense of simulated experience.
To overcome this drawback, a capability that enables a user to walk as desired with the viewpoint of the avatar of the user in a virtual space represented in three-dimensional graphics is realized by use of a three-dimensional graphics data description language called VRML (Virtual Reality Modeling Language) as disclosed in Japanese Patent Laid-open No. Hei 9-81781 corresponding to U.S. patent application Ser. No. 678,340. Considerations about various cyberspaces in which chat is made by use of the avatar of a user are described in NIKKEI Electronics, Sep. 9, 1996, No. 670, pp. 151-159.
Recently, breeding simulation games for breeding tropical fish and a virtual creature having artificial intelligence living in a virtual world for example have come to be available as personal computer software programs. A product is also known that displays a simulated pet such as a dog or a cat on an electronic notepad to enjoy the process of its growth (refer to NIKKEI Electronics, Apr. 7, 1997, No. 686, pp. 131-134). In addition, "Tamagotchi" (registered trademark) developed and commercialized by Bandai Co. is widely known that is an egg-sized portable virtual reality pet with a breeding simulation game program as mentioned above incorporated.
Virtual reality pets of this type have a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory) and so on mounted on a single-chip LSI (Large Scale Integration), a breeding simulation game program being stored in the ROM, the figure and state of the pet being displayed on an LCD (Liquid Crystal Display) device. The user gives such instructions by operating buttons as "feed" and "groom," for example, as necessary for breeding the virtual reality creature as a pet. As a result of caring, the virtual reality creature displayed on the LCD grows stepwise from an egg to a chick to a grown-up bird for example in its external view.
The virtual reality creature is programmed such that proper instructions help the virtual reality creature grow without problems and improper instructions make it sick or, in the worst case, die. Further, the virtual reality creature is programmed to make various requests based on the time elapsing from its birth provided by an incorporated calendar timer. For example, in the nighttime zone, the virtual reality creature requests a sleep and, in the mealtime zone, it requests food. In other times, the virtual reality creature requests, at random, snack and play for example. If the user fails to answer these requests properly, the growth of the virtual reality creature may be retarded or its character worsens. If the user answers properly, the life of the virtual reality creature is lengthened.
Japanese Patent Laid-open No. Hei 07-160853 corresponding to U.S. Pat. No. 5,572,646 discloses a technology applicable to an electronic notepad for example for displaying images according to the growth processes of a virtual reality creature such as an animal or a plant. To be more specific, bit-map images representing the growth processes of a plant character for example are stored in the ROM in the electronic notepad. The plant character according to the degree of growth is displayed on the LCD of the electronic notepad and, at the same time, characters representing plant growing elements (water, light, and fertilizer for example) are displayed. Necessary amounts of these growing elements are inputted by operating corresponding keys on the electronic notepad. The inputted values are set to a water amount register, a light amount register, and a fertilizer amount register respectively in the RAM of the electronic notepad. Based on the values set to these registers, a new degree of growth is computed. Then, the plant character corresponding to the computed degree of growth is read from the ROM to be displayed on the LCD. Thus, the plant growth process according to the state of cultivation by the user is displayed.
In the above-mentioned virtual reality pet, a virtual creature programmed beforehand is handled as one entity, in which a breeding simulation game progresses in a one-to-one relationship between the virtual reality pet and its keeper, the owner of the virtual reality pet. Therefore, it is impossible for remote persons other than the keeper to breed a virtual reality pet or observe its growth process. It is also impossible for two or more persons to share and breed one virtual reality creature.
Comparison between a virtual creature based on the above-mentioned virtual reality pet and a creature in the real world indicates that the virtual reality pet has no communication with other users than its keeper while the creature in the real world communicates with two or more human beings for its character shaping. This is a definite difference in growth process between these two creatures.
In the image displaying method for the virtual reality creature disclosed in Japanese Published Unexamined Patent Application No. Hei 07-160853 for example, the bit-map images representing the growth process stages of the character of the virtual reality creature are stored beforehand in the ROM. Then, according to the degree of growth, the character of the virtual reality creature is altered stepwise. Therefore, this approach cannot dynamically alter the creature's appearance according the change in height and weight for example taking place in the growth process of the creature. Implementing this dynamic alteration, if possible, requires a preparation of huge amounts of bit map images beforehand, which is not realistic.